The present invention is generally related to substituted [1,2,4]triazolo[1,5a]pyridine derivatives and more particularly to particular [1,2,4]triazolo[1,5a]pyridine compounds with activity as adenosine receptor ligands.
Adenosine modulates a wide range of physiological functions by interacting with specific cell surface receptors. The potential of adenosine receptors as drug targets was first reviewed in 1982. Adenosine is related both structurally and metabolically to the bioactive nucleotides adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and cyclic adenosine monophosphate (cAMP); to the biochemical methylating agent S-adenosyl-L-methione (SAM); and structurally to the coenzymes NAD, FAD and coenzyme A; and to RNA. Together adenosine and these related compounds are important in the regulation of many aspects of cellular metabolism and in the modulation of different central nervous system activities.
The receptors for adenosine have been classified as A1, A2A, A2B and A3 receptors, belonging to the family of G protein-coupled receptors. Activation of adenosine receptors by adenosine initiates signal transduction mechanism. These mechanisms are dependent on the receptor associated G protein. Each of the adenosine receptor subtypes has been classically characterized by the adenylate cyclase effector system, which utilizes cAMP as a second messenger. The A1 and A3 receptors, coupled with Gi proteins inhibit adenylate cyclase, leading to a decrease in cellular cAMP levels, while A2A and A2B receptors couple to Gs proteins and activate adenylate cyclase, leading to an increase in cellular cAMP levels. It is known that the Al receptor system include the activation of phospholipase C and modulation of both potassium and calcium ion channels. The A3 subtype, in addition to its association with adenylate cyclase, also stimulates phospholipase C and so activates calcium ion channels.
The A1 receptor (326-328 amino acids) was cloned from various species (canine, human, rat, dog, chick, bovine, guinea-pig) with 90-95% sequence identify among the mammalian species. The A2A receptor (409-412 amino acids) was cloned from canine, rat, human, guinea pig and mouse. The A2B receptor (332 amino acids) was cloned from human and mouse with 45% homology of human A2B with human A1 and A2A receptors. The A3 receptor (317-320 amino acids) was cloned from human, rat, dog, rabbit and sheep.
The A1 and A2A receptor subtypes are proposed to play complementary roles in adenosine""s regulation of the energy supply. Adenosine, which is a metabolic product of ATP, diffuses from the cell and acts locally to activate adenosine receptors to decrease the oxygen demand (A1) or increase the oxygen supply (A2A) and so reinstate the balance of energy supply versus demand within the tissue. The actions of both subtypes is to increase the amount of available oxygen to tissue and to protect cells against damage caused by a short-term imbalance of oxygen. One of the important functions of endogenous adenosine is preventing damage during traumas such as hypoxia, ischaemia, hypotension and seizure activity.
Furthermore, it is known that the binding of the adenosine receptor agonist to mast cells expressing the rat A3 receptor resulted in increased inositol triphosphate and intracellular calcium concentrations, which potentiated antigen induced secretion of inflammatory mediators. Therefore, the A3 receptor plays a role in mediating asthmatic attacks and other allergic responses.
Adenosine is also a neuromodulator, possessing global importance in the modulation of molecular mechanisms underlying many aspects of physiological brain function by mediating central inhibitory effects. An increase in neurotransmitter release follows traumas such as hypoxia, ischaemia and seizures. These neurotransmitters are ultimately responsible for neural degeneration and neural death, which causes brain damage or death of the individual. The adenosine A1 agonists which mimic the central inhibitory effects of adenosine may therefore be useful as neuroprotective agents. Adenosine has been proposed as an endogenous anticonvulsant agent, inhibiting glutamate release from excitory neurons and inhibiting neuronal firing. Adenosine agonists therefore may be used as antiepileptic agents. Adenosine antagonists stimulate the activity of the CNS and have proven to be effective as cognition enhancers. Selective A2a-antagonists have therapeutic potential in the treatment of various forms of dementia, for example in Alzheimer""s disease and are useful as neuroprotective agents. Adenosine A2-receptor antagonists inhibit the release of dopamine from central synaptic terminals and reduce locomotor activity and consequently improve Parkinsonian symptoms. The central activities of adenosine are also implicated in the molecular mechanism underlying sedation, hypnosis, schizophrenia, anxiety, pain, respiration, depression and substance abuse. Drugs acting at adenosine receptors therefore have also therapeutic potential as sedatives, muscle relaxants, antipsychotics, anxiolytics, analgesics, respiratory stimulants and antidepressants.
An important role for adenosine in the cardiovascular system is as a cardioprotective agent. Levels of endogenous adenosine increase in response to ischaemia and hypoxia, and protect cardiac tissue during and after trauma (preconditioning). Adenosine agonists thus have potential as cardioprotective agents.
Adenosine modulates many aspects of renal function, including renin release, glomerular filtration rate and renal blood flow. Compounds, which antagonise the renal affects of adenosine, have potential as renal protective agents. Furthermore, adenosine A3 and/or A2B antagonists may be useful in the treatment of asthma and other allergic responses.
Numerous documents describe the current knowledge on adenosine receptors, for example the following publications:
Bioorganic and Medicinal Chemistry, 6, (1998), 619-641,
Bioorganic and Medicinal Chemistry, 6, (1998), 707-719,
J. Med. Chem., (1998), 41, 2835-2845,
J. Med. Chem., (1998), 41, 3186-3201,
J. Med. Chem., (1998), 41, 2126-2133,
J. Med. Chem., (1999), 42, 706-721,
J. Med. Chem., (1996), 39, 1164-1171,
Arch. Pharm. Med. Chem., (1999), 332, 39-41.
The present invention is a compound of the formula 
wherein
R1 is unsubstituted lower alkoxy, cycloalkyl or aryl, or lower alkoxy, cycloalkyl or aryl substituted by halogen or lower alkoxy, or is xe2x80x94NRxe2x80x2Rxe2x80x3, wherein Rxe2x80x2 and Rxe2x80x3 are independently from each other hydrogen, lower alkyl, lower alkenyl, lower alkinyl, unsubstituted xe2x80x94(CR2)n-aryl, or xe2x80x94(CR2)n-aryl, substituted by one to three substituents, selected from the group, consisting of halogen or lower alkoxy, or are xe2x80x94(CH2)n+1NRa2, xe2x80x94(CH2)n-pyridinyl, xe2x80x94(CH2)n-indanyl, xe2x80x94(CH2)n-cycloalkyl, xe2x80x94(CH2)nxe2x80x94O-lower alkyl, xe2x80x94(CH2)nxe2x80x94C(O)xe2x80x94NRb2, xe2x80x94(CH2)nxe2x80x94CF3, or Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached unsubstituted pyrrolidin-1-yl, piperidin-1-yl, 3,4-dihydro-1H-isoquinolin-2-yl, morpholinyl, azatidin-1-yl, 3,6-dihydro-2H-pyridin-1-yl, thiomorpholinyl, 2,5-dihydro-pyrrol-1-yl, thiazolidin-3-yl, piperazinyl, azocan-1-yl, azepan-1-yl, octahydroquinolin-1-yl, octahydroquinolin-2-yl, 1,3,4,9-tetrahydro-b-carbolin-2-yl, or pyrrolidin-1-yl, piperidin-1-yl, 3,4-dihydro-1H-isoquinolin-2-yl, morpholinyl, azatidin-1-yl, 3,6-dihydro-2H-pyridin-1-yl, thiomorpholinyl, 2,5-dihydro-pyrrol-1-yl, thiazolidin-3-yl, piperazinyl, azocan-1-yl, azepan-1-yl, octahydroquinolin-1-yl, octahydroquinolin-2-yl, 1,3,4,9-tetrahydro-b-carbolin-2-yl, substituted by one to three substituents selected from the group consisting of lower alkyl, phenyl, benzyl, pyridyl, xe2x80x94C(O)xe2x80x94NRc2, xe2x80x94(CH2)nxe2x80x94O-lower alkyl or xe2x80x94NRdxe2x80x94(C(O)-lower alkyl;
R2 is unsubstituted aryl or a 5 or 6 membered heteroaryl group substituted by lower alkyl, halogen, hydroxy or lower alkoxy;
X is a bond or xe2x80x94N(Re)CH2xe2x80x94;
R, Ra, Rb, Rc, Rd, Re are independently hydrogen or lower alkyl;
n is 0, 1, 2, 3, 4, 5 or 6;
or a pharmaceutically acceptable salt thereof.
It has surprisingly been found that the compounds of formula I are adenosine receptor ligands.
Objects of the present invention are compounds of formula I and their pharmaceutically acceptable salts per se and as pharmaceutically active substances, their manufacture, pharmaceutical compositions based on a compound in accordance with the invention and their production as well as the use of compounds of formula I in the control or prevention of illnesses based on the modulation of the adenosine system, such as Alzheimer""s disease, Parkinson""s disease, neuroprotection, schizophrenia, anxiety, pain, respiration deficits, depression, asthma, allergic responses, hypoxia, ischaemia, seizure and substance abuse. Furthermore, compounds of the present invention may be useful as sedatives, muscle relaxants, antipsychotics, antiepileptics, anticonvulsants and cardiaprotective agents. The most preferred indications in accordance with the present invention are those, which are based on the A2A receptor antagonistic activity and which include disorders of the central nervous system, for example the treatment or prevention of certain depressive disorders, neuroprotection and Parkinson""s disease.
As used herein, the term xe2x80x9clower alkylxe2x80x9d denotes a saturated straight- or branched-chain alkyl group containing from 1 to 6 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, i-butyl, 2-butyl, t-butyl and the like. Preferred lower alkyl groups are groups with 1-4 carbon atoms.
As used herein, the term xe2x80x9clower alkenylxe2x80x9d denotes an unsaturated straight- or branched-chain, containing 2 to 6 carbon atoms and at least one double bond, for example, ethylen, propylen, isopropylen, n-butylen, i-butylen, 2-butylen, t-butylen and the like. Preferred lower alkenyl groups are groups with 2-4 carbon atoms.
As used herein, the term xe2x80x9clower alkinylxe2x80x9d denotes an unsaturated straight- or branched-chain, containing from 2 to 6 carbon atoms and containing at least one triple bond.
The term xe2x80x9ccycloalkylxe2x80x9d denotes a saturated carbocyclic group, containing 3-8 carbon atoms.
The term xe2x80x9chalogenxe2x80x9d denotes chlorine, iodine, fluorine and bromine.
The term xe2x80x9clower alkoxyxe2x80x9d denotes a group wherein the alkyl residue is as defined above, and which is attached via an oxygen atom.
The term xe2x80x9c5 or 6 membered heteroaryl groupxe2x80x9d denotes, but is not limited to, for example furanyl, thiophenyl, pyrrolyl, thiazolyl or pyridinyl and the like.
The term xe2x80x9carylxe2x80x9d denotes phenyl or naphthyl.
The term xe2x80x9cpharmaceutically acceptable acid addition saltsxe2x80x9d embraces salts with inorganic and organic acids, such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, citric acid, formic acid, fumaric acid, maleic acid, acetic acid, succinic acid, tartaric acid, methane-sulfonic acid, p-toluenesulfonic acid and the like.
Generally speaking, the most preferred are compounds of formula 1 wherein X is a bond. Compounds wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, Rxe2x80x2, Rxe2x80x3 and R2 are as above are also preferred.
Additional preferred compounds are compounds of formula 1 wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, Rxe2x80x2 and Rxe2x80x3 are independently from each other hydrogen, lower alkyl, lower alkenyl, lower alkinyl, xe2x80x94(CH2)nxe2x80x94C(O)xe2x80x94N(CH3)2, xe2x80x94(CH2)nxe2x80x94OCH3, xe2x80x94(CH2)n-cycloalkyl or xe2x80x94(CH2)n-pyridin-2-yl and R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl. Representative of these preferred compounds are compounds including:
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diethylamide,
5-amino-2-(5-methyl-thiophen-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclohexyl-ethyl-amide,
5-amino-2-(5-methyl-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclohexyl-methyl-amide,
5-amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butylamide,
(5-amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-pyrrolidin-1-yl-methanone
5-amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-propyl-amide,
5-amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-isopropyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-prop-2-ynyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid allyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-propyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid isopropyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-isopropyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diallylamide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diisopropylamide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butyl-ethyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-pentyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid (2-dimethylamino-ethyl)-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclopropylmethyl-propyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-(2-pyridin-2-yl-ethyl)-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dipropylamide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclohexyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid allyl-cyclopentyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclohexyl-ethyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diisobutylamide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-(2-pyridin-2-yl-ethyl)-amide,
1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-piperidine-3-carboxylic acid diethylamide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dimethylcarbamoylmethyl-methyl-amide,
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid (2-methoxy-ethyl)-methyl-amide and
5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-(2-methoxy-ethyl)-amide.
Other preferred compounds are compounds of formula 1 wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3 and wherein one of Rxe2x80x2 and Rxe2x80x3 is hydrogen and the other is lower alkyl and R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl Exemplary of this preferred compound is 5-Amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butylamide.
Another preferred compound is a compound of formula 1 wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3 or both Rxe2x80x2 and Rxe2x80x3 are lower alkyl and R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl. Exemplary of this preferred compound is 5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diethylamide;
5-Amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-propyl-amide;
5-Amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-isopropyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-methyl-amide;
5-Amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diethylamide
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid isopropyl-methyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butyl-methyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-isopropyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diisopropylamide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butyl-ethyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-pentyl-amide;
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dipropylamide; and
5-Amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diisobutylamide.
Yet more preferred compounds include the compound of formula 1 wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)n-cycloalkyl and the other is hydrogen, or one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)n-cycloalkyl and the other is lower alkyl, or both Rxe2x80x2 and Rxe2x80x3 are xe2x80x94(CH2)n-cycloalkyl and wherein n is 0, 1, 2, 3, 4, 5 or 6, and R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl. Further preferred compounds according to formula 1 are compounds wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl and wherein one of Rxe2x80x2 and Rxe2x80x3 lower alkyl and the other is lower alkinyl. Yet other preferred compounds of formula 1 are found when X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl, and wherein one of Rxe2x80x2 and Rxe2x80x3 lower alkyl and the other is lower alkenyl, or one is xe2x80x94(CH2)n-cycloalkyl and the other is lower alkenyl, or both Rxe2x80x2 and Rxe2x80x3 are lower alkenyl, and wherein n is 0, 1, 2, 3, 4, 5 or 6. Further preferred compounds according to formula 1 are found when X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl, and wherein one of Rxe2x80x2 and Rxe2x80x3 lower alkyl and the other is lower alkenyl, or one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)n-cycloalkyl and the other is lower alkenyl, and wherein one of Rxe2x80x2 and Rxe2x80x3 xe2x80x94(CH2)n-pyridinyl and the other is lower alkyl, and wherein n is 0, 1, 2, 3, 4, 5 or 6. Another preferred compound of formula 1 is wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is unsubstituted furyl or thiophenyl, or furyl or thiophenyl substituted by halogen or lower alkyl, and wherein one of Rxe2x80x2 and Rxe2x80x3 lower alkyl and the other is lower alkenyl, or one is xe2x80x94(CH2)n-cycloalkyl and the other is lower alkenyl, or wherein one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)nxe2x80x94OCH3 and the other is lower alkyl, and n is 0, 1, 2, 3, 4, 5 or 6.
Other preferred compounds of formula 1 are wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is as above, and one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)nxe2x80x94Nxe2x80x94(CH3)2 and the other is lower alkyl, and wherein n is 0, 1, 2, 3, 4, 5 or 6. Additional preferred compounds of formula 1 are where X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is as above and one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94NRxe2x80x94C(O)xe2x80x94Nxe2x80x94(CH3)2 and the other is lower alkyl, and wherein n is 0, 1, 2, 3, 4, 5 or 6.
Additional preferred compounds of formula 1 are seen when X is a bond, R1 is NRxe2x80x2Rxe2x80x3, wherein Rxe2x80x2 and Rxe2x80x3 are independently from each other hydrogen, lower alkyl, lower alkenyl, lower alkinyl, and R2 is thiazol-2-yl. Further preferred compounds of formula 1 are seen when X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl and wherein one of Rxe2x80x2 and Rxe2x80x3 is hydrogen and the other is lower alkyl. Yet more preferred compounds of formula 1 when X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl are compounds having Rxe2x80x2 and Rxe2x80x3 are lower alkyl. Additional preferred compounds of formula 1 wherein X is a bond, R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl are formed when one of Rxe2x80x2 and Rxe2x80x3 is lower alkyl and the other is lower alkenyl. Yet more preferred compounds of formula 1 when X is a bond R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl are formed when wherein one of Rxe2x80x2 and Rxe2x80x3 is lower alkyl and the other is lower alkinyl. Yet further preferred compounds of formula 1 are formed when X is a bond R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl, wherein one of Rxe2x80x2 and Rxe2x80x3 is xe2x80x94(CH2)n-pyridinyl and the other is lower alkyl and wherein n is 0, 1, 2, 3, 4, 5 or 6. Other preferred compounds of formula 1 when X is a bond R1 is NRxe2x80x2Rxe2x80x3, R2 is thiazol-2-yl are seen when wherein Rxe2x80x2 and Rxe2x80x3 are both xe2x80x94(CH2)n-aryl and wherein n is 0, 1, 2, 3, 4, 5 or 6.
Yet more preferred compounds of formula 1 are formed when X is a bond R1 is NRxe2x80x2Rxe2x80x3, and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached form unsubstituted pyrrolidinyl, piperidinyl, morpholinyl, 3,6-dihydro-2H-pyridin-1-yl, 2,5-dihydro-pyrrol-1-yl, azocan-1-yl; or pyrrolidinyl, piperidinyl, morpholinyl, 3,6-dihydro-2H-pyridin-1-yl, 2,5-dihydro-pyrrol-1-yl, azocan-1-yl, substituted by lower alkyl, lower alkoxy, xe2x80x94C(O)NH2, xe2x80x94C(O)N(CH3)2, or xe2x80x94N(CH3)xe2x80x94C(O)xe2x80x94CH3 and R2 is unsubstituted furyl or furyl substituted by halogen. Further preferred compounds of formula 1 when X is a bond and R1 is NRxe2x80x2Rxe2x80x3 are formed when NRxe2x80x2Rxe2x80x3 form unsubsituted pyrrolidinyl, piperidinyl, or morpholinyl and R2 is unsubstituted furyl or furyl substituted by halogen. Yet more compounds of formula 1 where X is a bond and R1 is NRxe2x80x2Rxe2x80x3 are formed when xe2x80x94NRxe2x80x2Rxe2x80x3 form substituted pyrrolidinyl, piperidinyl, morpholinyl, 3,6-dihydro-2H-pyridin-1-yl, 2,5-dihydro-pyrrol-1-yl, or azocan-1-yl; substituted by lower alkyl, lower alkoxy, xe2x80x94C(O)NH2, xe2x80x94C(O)N(CH3)2, or xe2x80x94N(CH3)xe2x80x94C(O)xe2x80x94CH3 and R2 is unsubstituted furyl or furyl substituted by halogen. Additional compounds of formula 1 where X is a bond and R1 is NRxe2x80x2Rxe2x80x3 are formed when NRxe2x80x2Rxe2x80x3 form substituted pyrrolidinyl, piperidinyl, morpholinyl, 3,6-dihydro-2H-pyridin-1-yl, 2,5-dihydro-pyrrol-1-yl, or azocan-1-yl; substituted by lower alkyl, lower alkoxy, xe2x80x94C(O)NH2, xe2x80x94C(O)N(CH3)2, or xe2x80x94N(CH3)xe2x80x94C(O)xe2x80x94CH3 and R2 is unsubstituted furyl or furyl substituted by halogen.
Further preferred compounds of formula 1 are formed when X is a bond, R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached form unsubstituted pyrrolidinyl, piperidinyl, octahydroquinolin-1-yl, 2,5-dihydro-pyrrol-1-yl, thiazolidinyl, thiazolyl, azepan-1-yl or azocan-1-yl and R2 is thiazolyl. Other preferred compounds of formula 1 are formed when X is a bond and wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached form substituted pyrrolidinyl, piperidinyl, octahydroquinolin-1-yl, 2,5-dihydro-pyrrol-1-yl, thiazolidinyl, thiazolyl, azepan-1-yl or azocan-1-yl, wherein said substituents are lower alkyl, and R2 is thiazolyl. Yet other preferred compounds of formula 1 include compounds wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 together with the N atom to which they are attached form unsubstituted pyrrolidin-1-yl, azepan-1-yl, piperidin-1-yl, or azocan-1-yl, or substituted pyrrolidin-1-yl, azepan-1-yl, piperidin-1-yl, or azocan-1-yl, and wherein said substituents are lower alkyl or lower alkoxy, and R2 is pyridyl. Additional preferred compounds of formula 1 are formed when X is a bond, R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 together with the N atom to which they are attached form unsubstituted substituted pyrrolidin-1-yl, azepan-1-yl, piperidin-1-yl, or azocan-1-yl and R2 is pyridyl. Yet more preferred compounds of formula I include compounds where X is a bond, R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 together with the N atom to which they are attached form substituted pyrrolidin-1-yl, azepan-1-yl, piperidin-1-yl, or azocan-1-yl, and wherein said substituents are lower alkyl or lower alkoxy and R2 is pyridyl.
Other preferred compounds of formula 1 are compounds wherein X is a bond, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are independently from each other lower alkenyl, lower alkyl, xe2x80x94(CH2)n-cycloalkyl, xe2x80x94(CH2)n-pyridinyl or xe2x80x94(CH2)n-phenyl and R2 is pyridyl.
Compound of formula I, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are independently from each other lower alkyl, lower alkenyl, lower alkinyl, xe2x80x94(CH2)n-phenyl or xe2x80x94(CH2)n-pyridinyl and R2 is thiazolyl are further preferred.
Such compounds are
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butylamide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diethylamide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-methyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-prop-2-ynyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid allyl-methyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid methyl-propyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid isopropyl-methyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid butyl-methyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-pyridin-4-ylmethyl-amide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dibenzylamide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethylamide,
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dipropylamide or
5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diisobutylamide.
Preferred are compounds of formula I, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached pyrrolidinyl, piperidinyl, morpholinyl, 3,6-dihydro-2H-pyridin-1-yl, 2,5-dihydro-pyrrol-1-yl, azocan-1-yl, and wherein the rings may be unsubstituted or substituted by lower alkyl, lower alkoxy, xe2x80x94C(O)NH2, xe2x80x94C(O)N(CH3)2, xe2x80x94N(CH3)xe2x80x94C(O)xe2x80x94CH3 and R2 is furyl unsubstituted or substituted by halogen.
Examples of such compounds are
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-pyrrolidin-1-yl-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-piperidin-1-yl-methanone,
(5-amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-pyrrolidin-1-yl-methanone,
(5-amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-piperidin-1-yl-methanone,
(5-amino-2-furan-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-morpholin-4-yl-methanone,
[5-amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(3,6-dihydro-2-H-pyridin-1-yl)-methanone,
[5-amino-2-(5-chloro-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2-methyl-pyrrolidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2,5-dihydro-pyrrol-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2-methyl-pyrrolidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2,5-dihydro-pyrrol-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2,5-pyrrolidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2,6-morpholin-4-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(2-methyl-piperidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(4-methyl-piperidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-azocan-1-yl-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(3,5-dimetyl-piperidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-[(2R,5R)-trans-2,5-dimethyl-pyrrolidin-1-yl]-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(cis-2,6-dimethyl-morpholin-4-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(S-2-methoxymethyl-pyrrolidin-1-yl)-methanone,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(R-2-methoxymethyl-pyrrolidin-1-yl)-methanone,
1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-L-pyrrolidine-2-carboxylic acid amide,
1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-D-pyrrolidine-2-carboxylic acid amide,
1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-pyrrolidine-2-carboxylic acid dimethylamide,
N-{1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-pyrrolidin-3-yl}-N-methyl-acetamide,
[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridin-7-yl]-(5-ethyl-2-methyl-piperidin-1-yl)-methanone or
1-[5-amino-2-(5-bromo-furan-2-yl)-[1,2,4]triazolo[1,5-a]pyridine-7-carbonyl]-piperidine-3-carboxylic acid amide.
Compounds of formula I, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached pyrrolidinyl, piperidinyl, octahydroquinolin-1-yl, 2,5-dihydro-pyrrol-1-yl, thiazolidinyl, thiazolyl, azepan-1-yl or azocan-1-yl, and wherein the rings may be unsubstituted or substituted by lower alkyl, and R2 is thiazolyl, are also preferred, for example the followings:
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-pyrrolidin-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-piperidin-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2,5-dihydro-pyrrol-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2-methyl-pyrrolidin-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-thiazolidin-3-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-azepan-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2-methyl-piperidin-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(4-methyl-piperidin-1-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-azocan-1-yl-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(3,5-dimethyl-piperidin-1-yl)-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2,6-dimethyl-piperidin-1-yl)-methanone,
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(cis-2,6-dimethyl-piperidin-1-yl)-methanone or
(5-amino-2-thiazol-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(octahydro-quinolin-1-methanone.
Further preferred are compounds of formula I, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are together with the N atom to which they are attached pyrrolidin-1-yl, azepan-1-yl, piperidin-1-yl, azocan-1-yl, and wherein the rings may be unsubstituted or substituted by lower alkyl, lower alkoxy and R2 is pyridyl.
Examples of such compounds are:
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2-methyl-pyrrolidin methanone,
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-azepan-1-yl-methanone,
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2-methyl-piperidin-1-yl-methanone,
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(2-methyl-piperidin-1-yl-methanone,
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-azocan-1-yl-methanone,
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-(3,5-dimethyl-piperidin-1-yl)-methanone or
(5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridin-7-yl)-R-2-methoxymethyl-pyrrolidin-1-yl)-methanone.
Compounds of formula I, wherein R1 is xe2x80x94NRxe2x80x2Rxe2x80x3 and Rxe2x80x2 and Rxe2x80x3 are independently from each other lower alkenyl, lower alkyl, xe2x80x94(CH2)n-cycloalkyl, xe2x80x94(CH2)n-pyridinyl or xe2x80x94(CH2)n-phenyl and R2 is pyridyl are further preferred, for example the followings:
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid diallylamide,
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid cyclopropylmethyl-propyl-amide,
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid allyl-cyclopentyl-amide,
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid ethyl-pyridin-4-yl-methyl-amide,
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid benzyl-isopropyl-amide or
5-amino-2-pyridin-2-yl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid dibenzylamide.
Further preferred are compounds of formula I, wherein X is xe2x80x94N(Re)CH2xe2x80x94 and R1 is cycloalkyl or aryl, unsubstituted or substituted by halogen and R2 is furyl, unsubstituted or substituted by halogen or methyl, or is thiazolyl.
The present compounds of formula I and their pharmaceutically acceptable salts can be prepared by methods known in the art, for example, by processes described below, which process comprises
reacting a compound of formula 
with a compound of formula
HNRxe2x80x2Rxe2x80x3xe2x80x83xe2x80x83II
to a compound of formula 
wherein R1, R2 and Rxe2x80x2 and Rxe2x80x3 have the significances given above, or
reacting a compound of formula 
with a compound of formula
R2CHOxe2x80x83xe2x80x83V
in the presence of a compound of formula 
o give a compound of formula 
wherein R1 and R2 are defined above, or
reacting a compound of formula 
with HCl and then with a compound of formula 
and with a compound of formula
R2CHOxe2x80x83xe2x80x83V
to a compound of formula 
wherein R1 and R2 have the significances given above or
modifying one or more substituents R1 or R2 within the definitions given above, and
if desired, converting the compounds obtained into pharmaceutically acceptable acid addition salts.
In Examples 1-435 and in the following schemes 1 and 2 the preparation of compounds of formula I is described in more detail. 
Scheme 1 describes the process for preparation of 2,6-diamino-isonicotinic acid methyl ester (X), which is the starting material for further processes to obtain a compound of formula I. In accordance with scheme 1, 2,6-dichloroisonicotinic acid (commercial product, VIII) is mixed with copper powder in aqueous ammonia, and the mixture is heated for about 12 hours in an autoclave. After cooling to room temperature the copper was filtered off and the filtrate is treated with HCl to pH=5. The obtained 2,6-diamino-isonicotinic acid (IX) is solved in methanol and treated at 0xc2x0 C. with gaseous HCl. The mixture is concentrated, dissolved in water and saturated NaHCO3 is added to pH=8. The 2,6-diamino-isonicotinic acid methyl ester (X) is obtained after extraction with ethylacetate. 
The substituents R1 and R2 have the significances given above.
In accordance with scheme 2 compounds of formulas I-1, I-2, I-3 and I-4 are obtained. Compounds of formula I, wherein R1 is methoxy (I-1), may be prepared as follows: To a solution of 2,6-diamino-isonicotinic acid methyl ester (X) in dioxane is added O-mesitylenesulfonylhydroxylamine (IV) and a corresponding aldehyde (V). The mixture is stirred for some hours at about 100xc2x0 C. After addition of KOH in methanol the solution is stirred at room temperature and then the product is concentrated.
The obtained compound of formula I-1 may further be transformed into a compound of formula I-2. To a solution of a compound of formula II in dioxane is added trimethylaluminum or methylaluminoxane and stirred for about 1 hour at room temperature. Then a mixture of a compound of formula I-1 in dioxane is added and the mixture is heated at about 80xc2x0 C. for 72 hours. After addition of HCl the compound of formula I-2 is obtained.
A compound of formula I-3 may be prepared as follows: A solution of 2,6-diamino-isonicotinic acid methyl ester (X) is treated for 1 hour with gaseous ammonia. The mixture is heated for 36 hours at about 60xc2x0 C. in an autoclave and is then filtered through decalite. The obtained 2,6-diamino-isonicotinamide is suspended in THF and boran-dimethylsulfide-complex (or NaBH4) is added. The mixture is refluxed for 4 days. After cooling to room temperature HCl is added and the mixture is neutralized with NaOH, to give 4-aminomethyl-pyridine-2,6-diamine. A solution of this compound in pyridine is treated with a compound of formula XII together with a catalytic amount of 4-dimethylaminopyridine, and stirred for 2.5 hours at room temperature to obtain a compound of formula III. Furthermore, to the obtained solution of a compound of formula III in dioxane is added O-mesitylenesulfonylhydroxylamine and then an aldehyde of formula V. The mixture is heated to about 100xc2x0 C. and after 2.5 hours KOH in methanol is added. After stirring the mixture at room temperature a compound of formula I-3 is obtained.
Compounds of formula I-4 may be prepared as follows: A mixture of 2,6-diamino-isonicotinic acid methyl ester (X), pyridine and acetic anhydride is stirred for 1 hour at room temperature and subsequently 1 hour at about 80xc2x0 C. After purification the prepared 2,6-bis-acetylamino-isonicotinic acid methyl ester is solved in pyridine and is added slowly to a mixture of N,O-dimethylhydroxylamide and trimethylaluminum in toluene and is then allow to stir to room temperature. After purification a compound of formula XIII is obtained. Further, to a solution of 2,6-bis-acetylamino-N-methoxy-N-methyl-isonicotinamide (XIII) is added at room temperature a solution of a compound of formula R1MgBr, for example 4-fluorophenylmagnesium bromide, in THF. The solution is stirred at room temperature and subsequently for 2 hours at about 40xc2x0 C. After cooling to room temperature HCl is added and the mixture is evaporated to dryness. After purification a compound of formula VI is obtained. This compound is solved in dioxane and O-mesitylenesulfonylhydroxylamine and a compound of formula V, for example 5-bromo-2-furaldehyde, is added. The mixture is stirred at about 80xc2x0 C. for 30 min, and after the addition of KOH the mixture is stirred at room temperature for some hours. After purification of the mixture a compound of formula I4 is obtained.
The salt formation is effected at room temperatures in accordance with methods which are known per se and which are familiar to any person skilled in the art. Not only salts with inorganic acids, but also salts with organic acids came into consideration. Hydrochlorides, hydrobromides, sulphates, nitrates, citrate, acetates, maleates, succinates, methan-sulphonates, p-toluenesulphonates and the like are examples of such salts.
The compounds of formula I and their pharmaceutically usable addition salts possess valuable pharmacological properties. Specifically, it has been found that the compounds of the present invention are adenosine receptor ligands.
The compounds were investigated in accordance with the tests given hereinafter.
The human adenosine A2A receptor was recombinantly expressed in chinese hamster ovary (CHO) cells using the semliki forest virus expression system. Cells were harvested, washed twice by centrifugation, homogenized and again washed by centrifugation. The final washed membrane pellet was suspended in a Tris (50 mM) buffer containing 120 mM NaCl, 5 mM KCl, 2 mM CaCl2 and 10 MM MgCl2 (pH 7.4) (buffer A). The [3H]-SCH-58261 (Dionisotti et al., 1997, Br. J. Pharmacol. 121, 353) binding assay was carried out in 96-well plates in the presence of 2.5 xcexcg of membrane protein, 0.5 mg of Ysi-poly-1-lysine SPA beads and 0.1 U adenosine deaminase in a final volume of 200 xcexcl of buffer A. Non-specific binding was defined using xanthine amine congener (XAC; 2 xcexcM). Compounds were tested at 10 concentrations from 10 xcexcM-0.3 nM. All assays were conducted in duplicate and repeated at least two times. Assay plates were incubated for 1 hour at room temperature before centrifugation and then bound ligand determined using a Packard Topcount scintillation counter. IC50 values were calculated using a non-linear curve fitting program and Ki values calculated using the Cheng-Prussoff equation.
In accordance with the invention, it has been shown that compounds of formula I have a high affinity toward the A2A receptor. In the table below are described specific values of prepared compounds. Values of KiHA2A and KiHA1 are shown for compounds of formula 1. A low Ki value is indicative of a particular compound""s high affinity toward a particular receptor and conversely a higher Ki value is indicative of a lower affinity for that compound toward a particular receptor. A ratio obtained by dividing KiHA1 by KiHA2A is then calculated. This calculated ratio provides a measure of the selectivity of the compound between the A2A receptor and the A1 receptor. Generally speaking, compounds that have a higher HA1/HA2A ratio are able to give a substantially complete blockade of the HA2A receptor without substantially affecting the A1 receptor.
The compounds of formula I and the pharmaceutically acceptable salts of the compounds of formula I can be used as pharmaceutical compositions. The pharmaceutical compositions can be administered orally, e.g. in the form of tablets, coated tablets, dragxc3xa9es, hard and soft gelatine capsules, solutions, emulsions or suspensions. The administration can, however, also be effected rectally, e.g. in the form of suppositories, parenterally, e.g. in the form of injection solutions.
The compounds of formula I can be processed with pharmaceutically inert, inorganic or organic carriers and other pharmaceutically acceptable excipients for the production of pharmaceutical compositions. Lactose, corn starch or derivatives thereof, talc, stearic acids or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragxc3xa9es and hard gelatine capsules. Suitable carriers for soft gelatine capsules are, for example, vegetable oils, waxes, fats, semi-solid and liquid polyols and the like. Depending on the nature of the active substance no carriers are, however, usually required in the case of soft gelatine capsules. Suitable carriers for the production of solutions and syrups are, for example, water, polyols, glycerol, vegetable oil and the like. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi-liquid or liquid polyols and the like.
The pharmaceutical compositions can, moreover, contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.
Pharmaceutical compositions containing a compound of formula I or a pharmaceutically acceptable salt thereof and a therapeutically inert carrier or pharmaceutically acceptable excipient are also an object of the present invention, as is a process for their production, which comprises bringing one or more compounds of formula I and/or pharmaceutically acceptable acid addition salts and, if desired, one or more other therapeutically valuable substances into a galenical administration form together with one or more therapeutically inert carriers.
In accordance with the invention compounds of formula I as well as their pharmaceutically acceptable salts are useful in the control or prevention of illnesses based on the adenosine receptor antagonistic activity, such as Alzheimer""s disease, Parkinson""s disease, neuroprotection, schizophrenia, anxiety, pain, respiration deficits, depression, asthma, allergic responses, hypoxia, ischaemia, seizure and substance abuse. Furthermore, compounds of the present invention may be useful as sedatives, muscle relaxants, antipsychotics, antiepileptics, anticonvulsants and cardiaprotective agents and for the production of corresponding medicaments.
The most preferred indications in accordance with the present invention are those, which include disorders of the central nervous system, for example the treatment or prevention of certain depressive disorders, neuroprotection and Parkinson""s disease.
The dosage can vary within wide limits and will, of course, have to be adjusted to the individual requirements in each particular case. In the case of oral administration the dosage for adults can vary from about 0.01 mg to about 1000 mg per day of a compound of formula I or of the corresponding amount of a pharmaceutically acceptable salt thereof. The daily dosage may be administered as single dose or in divided doses and, in addition, the upper limit can also be exceeded when this is found to be indicated.
Manufacturing Procedure
1. Mix items 1, 2, 3 and 4 and granulate with purified water.
2. Dry the granules at 50xc2x0 C.
3. Pass the granules through suitable milling equipment.
4. Add item 5 and mix for three minutes; compress on a suitable press.
Manufacturing Procedure
1. Mix items 1, 2 and 3 in a suitable mixer for 30 minutes.
2. Add items 4 and 5 and mix for 3 minutes.
3. Fill into a suitable capsule.